The present invention concerns an automatic apparatus for developing photographic films or the like, particularly color films.
Until now, generally the development of color photographs has required recourse to specialized centers which are unwieldly, bulky and costly; often resulting in delays of about 24 hours, and which do not permit economic development as soon as each film is ready for processing.
Although automatic apparatus for the development of films have previously been proposed (see for example the Journal of Applied Spectroscopy, Vol. 18, No. 1, 1975, pages 129-131, and U.S. Pat. Nos. 1,794,996, 2,975,695, and 3,494,273), none of such solutions are adapted to color film processing and they do not permit instantaneous service.
A device for the processing of black and while films is disclosed in U.S. Pat. No. 3,443,503 which consists of:
a plurality of treatment tanks arranged in a ring within a light-tight box,
a film-holder arm which is continuously rotated having a base which is arranged at the center of the ring,
a first cam path on which said arm rests adapted to advance the film within a treatment tank and to pass it into the next tank, and
a second undulated cam path adapted to agitate the film in a given tank.
However, the above device is for the development of black and white films such as dental negatives and cannot be readily used for the development of color films since: (1) the agitation imparted by the second cam path is definitely insufficient to permit an effective renewal of the bath which becomes depleted or ineffective after contact with the films during the course of the development; and (2) since the arm turns continuously, the angular displacement of this arm (which allows passage from one tank to the next) and the agitation of this arm in a given tank are simultaneous. This second drawback results in an invariable operating cycle and as a consequence, it is not possible to take into account the speed of the films to be treated unless large and bulky tanks are used to permit a variable time of stay from one tank to the next.
A similar type of apparatus is disclosed in U.S. Pat. No. 2,927,521 wherein a plurality of film-holder arms are lifted in order to provide passage from one tank to the next by means of a horizontal cam which is rotated continuously by a motor associated with a turntable and an upright bearing the film-holder arms. This device is also unsuitable for the development of color films since the agitation is insufficient and the cycle is invariable.
A further drawback encountered in utilizing the devices disclosed in the above U.S. Pat. Nos. 3,443,502 and 2,927,521 is that development of films wound on special spools known as "spirals" (whereby the film is wound spirally from the outside towards the inside), is scarcely conceivable without incurring rapid wear of the various moving mechanisms.